NEMO-3 experiment First Results and Future Prospects Ruben Saakyan, UCL UK HEP Neutrino Forum The Coseners House, Abingdon

Outline Why NEMO-3 ? The Detector First results Sensitivity by 2007 Towards SuperNEMO

Currently Active Experiments = 0.4 eV ??? CUORICINO (bolometer) NEMO-3 (Tracking calorimeter) Heidelberg-Moscow exp is still running

Why NEMO-3 ? One of the two experiments to improve sensitivity before 2007/2008 ( eV) for a few isotopes Well known (for us) technique orthogonal to other approaches Excellent chance to understand nitty gritty of experiment…..and choose a project to attack n×10 -2 eV scale

Neutrino Ettore Majorana Observatory 50 physicists and engineers 13 Laboratories/Universities 7 Countries

UK NEMO team (so far) Phil Adamson, Leo Jenner, Ruben Saakyan, Jenny Thomas (all UCL) Received approval from PPRP 27 Jan 03 Main involvement: data analysis....but also some hardware tasks (PMT helium tests, light injection optimization)

From scintil detector: = 250 ps From tracker: || = 1cm = 0.45mm (using timing information on plasma propagation) Calibration: Laser survey neutron Am/Be for ||,, e + signature e Bi, 90 Sr for energy calibration 60 Co for time alignment Trigger: 1 scintillator hit > 150 keV + 1 track: few Geiger planes (flexible 3 – 7 Hz)

Pure materials: Source foils measured with the NEMO-3 detector 208 Tl < 2 Bq/kg 214 Bi < 2 Bq/kg neutrons < n cm -2 s -1 Radon in the detector 222 Rn ~ 20 mBq/m Rn ~ 1.6 mBq/m 3 to be improved with new anti-radon system

Data taking June 2002: start with all 20 sectors, iron shielding, neutron shielding but… …still a lot of debugging (both tracking detector and calorimeter) 14 February 2003: start of routine data taking

NEMO events 3D pictures study single electron spectra study angular distributions Detailed 2 information O (10 5 ) Mo events/yr ! 7 isotopes

NEMO background events e + e - e - (~7 MeV) from n

NEMO-3 First Results 100 Mo 1200 h 2 : T 1/2 =[7.4±0.05(stat)±0.8(sys)]×10 18 yr (19000 events; S/B 50) 0 : 1 event in 2.8 – 3.2 MeV region T 1/2 > yr 90% CL < 0.9 – 2.1 eV Worlds best result for 100 Mo

Single State Dominance (SSD) VS Higher order State Dominance (HSD) Simkovic, Domin, Semenov nucl-th/ , Phys. Rev. C 100 Mo 100 Tc 100 Ru SSD HSD 1.Shape of single e - spectrum 2.Shape of 2 spectrum 3.Angular distribution 4.~ 20% difference in T 1/2 100 Mo + NEMO-like detector can test it experimentally !

NEMO-3 First Results 100 Mo 1200 h single e - spectrum Angular distribution between two e - Preliminary: SSD is preferred

NEMO-3 First Results Other Isotopes T 1/2 =[8.2±0.4(stat)±0.8(sys)]×10 19 T 1/2 > 4 × y 90% CL Worlds best result ! T 1/2 =[7.0±0.7(stat)±0.7(sys)]×10 18 T 1/2 > 7.7 × y 90% CL T 1/2 =[3.9±0.3(stat)±0.4(sys)]×10 19 T 1/2 > 1.0 × y 90% CL 82 Se 150 Nd 116 Cd

NEMO-3 0 sensitivity 5 years 100 Mo 7 kg Q =3.034 MeV External BG: 0 Internal BG: radioactivity < 0.04 event/y/kg = 0.11 event/y/kg T 1/2 > 3 × yr < 0.2 – 0.5 eV E = 2.8 – 3.2 MeV 82 Se 1 kg Q =2.995 MeV External BG: 0 Internal BG: radioactivity < 0.01 event/y/kg = 0.01 event/y/kg T 1/2 > 1 × yr < 0.6 – 1.2 eV In case of full load of 82 Se (~14kg) < 0.15 – 0.3 eV

SuperNEMO (not an official proposal yet) Sensitivity ~ 0.05 eV in 5 yr ~ 100 kg 82 Se (or other) 4 supermodules, planar geometry Feasible if: a)BG only from 2 (NEMO3) b) E/E = 10-11% at 1 MeV (R&D needed)

Future projects comparison ExperimentSource and Mass Sensitivity to T 1/2 (y) Sensitivity to (eV) * Majorana $50M 76 Ge, 500kg3× – 0.07 CUORE $25M 130 Te, 750kg(nat) 2× – 0.17 EXO $50M-100M 136 Xe 1 ton 8× – 0.12 SuperNEMO $20M 82 Se (or other) 100 kg 2× – 0.11 * 5 different latest NME calculations

Concluding Remarks 1200 h, T 1/2 (2 ) for 4 isotopes; Worlds best results for T 1/2 (0 ) for 100 Mo, 82 Se By 2007/2008 NEMO-3 to reach < eV (depending on 82 Se availability) Several isotopes will be investigated Unprecedented high 2 statistics with detailed information (single e - spectra, angular distributions) for 7 isotopes Experimental input to NME calculation

Concluding Remarks II NEMO-3 will test experimentally feasibility of SuperNEMO If yes 0.05 eV is achievable at relatively low cost and with very well known technology If not will not waste time and money and do something else

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